SEVEN YEARS’ WAR, the name given to the third and most terrible struggle between Frederick the Great of Prussia and Maria Theresa, empress of Austria, for, the possession of Silesia, which embroiled almost all Europe in war, and which had far-reaching effects on the destinies of England and France as well as Prussia; began in 1756 by Frederick’s successful advance on Dresden, anticipating Maria Theresa’s intention of attempting the recovery of Silesia, lost to her in the previous two wars.  With Austria were allied France, Sweden, Poland, and Russia, while Prussia was supported till 1761 by England.  In 1762 Peter III. of Russia changed sides, and Frederick, sometimes victorious, often defeated, finally emerged successful in 1763, when the war was brought to a close by the Peace of Hubertsburg.  Besides demonstrating the strength and genius of Frederick and raising immensely the prestige of Prussia, it enabled England to make complete her predominance in North America and to establish herself securely in India, while at the same time it gave the death-blow to French hopes of a colonial empire.

SEVERN, the second river of England, rises on the E. side of Plinlimmon, in Montgomeryshire, and flows in a circuitous southerly direction through Montgomeryshire, Shropshire, Worcestershire, and Gloucestershire, falling into the Bristol Channel after a course of 210 m.; is navigable to Welshpool (180 m.); chief tributaries are the Terne, Wye, and the Stratford Avon; there is a “bore” perceptible 180 m. from the mouth.

SEVERUS, L. SEPTIMIUS, Roman emperor, born in Leptis Magna, in Africa; was in command at Pannonia, and elected emperor on the murder of Pertinax, and after conquering his rivals achieved victories in the East, especially against the Parthians, and thereafter subdued a rebellion in Britain, and secured South Britain against invasions from the north by a wall; died at York (146-211).

SEVIGNE, MADAME DE, maiden name Marie de Rabutin-Chantal, the most charming of letter-writers, born at Paris; married at 18 the dissolute Marquis de Sevigne, who left her a widow at 25; her beauty and rare charms attracted many suitors, to one and all of whom, however, she turned a deaf ear, devoting herself with touching fidelity to her son and daughter, and finding all her happiness in their affection and in the social intercourse of a wide circle of friends; her fame rests on her letters, written chiefly to her daughter in Provence, which reflect the brightest and purest side of Parisian life, and contain the tender outpourings of her mother’s heart in language of unstudied grace (1626-1696).